NO179187B - Gellable aqueous mixture and process for reducing the permeability of a high permeability zone in an oil reservoir - Google Patents
Gellable aqueous mixture and process for reducing the permeability of a high permeability zone in an oil reservoir Download PDFInfo
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- NO179187B NO179187B NO901443A NO901443A NO179187B NO 179187 B NO179187 B NO 179187B NO 901443 A NO901443 A NO 901443A NO 901443 A NO901443 A NO 901443A NO 179187 B NO179187 B NO 179187B
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- linking agent
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- 239000000203 mixture Substances 0.000 title claims description 50
- 230000035699 permeability Effects 0.000 title claims description 25
- 238000000034 method Methods 0.000 title claims description 12
- 238000001879 gelation Methods 0.000 claims description 22
- 239000000872 buffer Substances 0.000 claims description 20
- 239000003431 cross linking reagent Substances 0.000 claims description 20
- 239000007864 aqueous solution Substances 0.000 claims description 16
- -1 Cr(III) ion Chemical class 0.000 claims description 12
- 229920002401 polyacrylamide Polymers 0.000 claims description 11
- BFGKITSFLPAWGI-UHFFFAOYSA-N chromium(3+) Chemical compound [Cr+3] BFGKITSFLPAWGI-UHFFFAOYSA-N 0.000 claims description 9
- 229920000620 organic polymer Polymers 0.000 claims description 9
- 238000002347 injection Methods 0.000 claims description 8
- 239000007924 injection Substances 0.000 claims description 8
- 150000007530 organic bases Chemical class 0.000 claims description 7
- 229920001222 biopolymer Polymers 0.000 claims description 6
- RAXXELZNTBOGNW-UHFFFAOYSA-N imidazole Natural products C1=CNC=N1 RAXXELZNTBOGNW-UHFFFAOYSA-N 0.000 claims description 6
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 claims description 4
- GLUUGHFHXGJENI-UHFFFAOYSA-N Piperazine Chemical compound C1CNCCN1 GLUUGHFHXGJENI-UHFFFAOYSA-N 0.000 claims description 4
- NQRYJNQNLNOLGT-UHFFFAOYSA-N Piperidine Chemical compound C1CCNCC1 NQRYJNQNLNOLGT-UHFFFAOYSA-N 0.000 claims description 4
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 claims description 4
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 claims description 4
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 claims description 4
- DMBHHRLKUKUOEG-UHFFFAOYSA-N diphenylamine Chemical compound C=1C=CC=CC=1NC1=CC=CC=C1 DMBHHRLKUKUOEG-UHFFFAOYSA-N 0.000 claims description 4
- AWJUIBRHMBBTKR-UHFFFAOYSA-N isoquinoline Chemical compound C1=NC=CC2=CC=CC=C21 AWJUIBRHMBBTKR-UHFFFAOYSA-N 0.000 claims description 4
- 239000003446 ligand Substances 0.000 claims description 4
- RNVCVTLRINQCPJ-UHFFFAOYSA-N o-toluidine Chemical compound CC1=CC=CC=C1N RNVCVTLRINQCPJ-UHFFFAOYSA-N 0.000 claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- 229910002651 NO3 Inorganic materials 0.000 claims description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 3
- SRSXLGNVWSONIS-UHFFFAOYSA-N benzenesulfonic acid Chemical compound OS(=O)(=O)C1=CC=CC=C1 SRSXLGNVWSONIS-UHFFFAOYSA-N 0.000 claims description 3
- 238000011065 in-situ storage Methods 0.000 claims description 3
- 229910021645 metal ion Inorganic materials 0.000 claims description 3
- 235000005985 organic acids Nutrition 0.000 claims description 3
- 230000009467 reduction Effects 0.000 claims description 3
- 239000000230 xanthan gum Substances 0.000 claims description 3
- 229920001285 xanthan gum Polymers 0.000 claims description 3
- 235000010493 xanthan gum Nutrition 0.000 claims description 3
- 229940082509 xanthan gum Drugs 0.000 claims description 3
- RAIPHJJURHTUIC-UHFFFAOYSA-N 1,3-thiazol-2-amine Chemical compound NC1=NC=CS1 RAIPHJJURHTUIC-UHFFFAOYSA-N 0.000 claims description 2
- HYZJCKYKOHLVJF-UHFFFAOYSA-N 1H-benzimidazole Chemical compound C1=CC=C2NC=NC2=C1 HYZJCKYKOHLVJF-UHFFFAOYSA-N 0.000 claims description 2
- AOPBDRUWRLBSDB-UHFFFAOYSA-N 2-bromoaniline Chemical compound NC1=CC=CC=C1Br AOPBDRUWRLBSDB-UHFFFAOYSA-N 0.000 claims description 2
- IKCLCGXPQILATA-UHFFFAOYSA-N 2-chlorobenzoic acid Chemical compound OC(=O)C1=CC=CC=C1Cl IKCLCGXPQILATA-UHFFFAOYSA-N 0.000 claims description 2
- SLAMLWHELXOEJZ-UHFFFAOYSA-N 2-nitrobenzoic acid Chemical compound OC(=O)C1=CC=CC=C1[N+]([O-])=O SLAMLWHELXOEJZ-UHFFFAOYSA-N 0.000 claims description 2
- DHYHYLGCQVVLOQ-UHFFFAOYSA-N 3-bromoaniline Chemical compound NC1=CC=CC(Br)=C1 DHYHYLGCQVVLOQ-UHFFFAOYSA-N 0.000 claims description 2
- PWRBCZZQRRPXAB-UHFFFAOYSA-N 3-chloropyridine Chemical compound ClC1=CC=CN=C1 PWRBCZZQRRPXAB-UHFFFAOYSA-N 0.000 claims description 2
- QSNSCYSYFYORTR-UHFFFAOYSA-N 4-chloroaniline Chemical compound NC1=CC=C(Cl)C=C1 QSNSCYSYFYORTR-UHFFFAOYSA-N 0.000 claims description 2
- TYMLOMAKGOJONV-UHFFFAOYSA-N 4-nitroaniline Chemical compound NC1=CC=C([N+]([O-])=O)C=C1 TYMLOMAKGOJONV-UHFFFAOYSA-N 0.000 claims description 2
- 239000005711 Benzoic acid Substances 0.000 claims description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 claims description 2
- 229920002907 Guar gum Polymers 0.000 claims description 2
- 239000004354 Hydroxyethyl cellulose Substances 0.000 claims description 2
- 229920000881 Modified starch Polymers 0.000 claims description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 2
- FZWLAAWBMGSTSO-UHFFFAOYSA-N Thiazole Chemical compound C1=CSC=N1 FZWLAAWBMGSTSO-UHFFFAOYSA-N 0.000 claims description 2
- 125000001931 aliphatic group Chemical group 0.000 claims description 2
- 150000001412 amines Chemical class 0.000 claims description 2
- 125000003118 aryl group Chemical group 0.000 claims description 2
- 235000010233 benzoic acid Nutrition 0.000 claims description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 2
- 235000010948 carboxy methyl cellulose Nutrition 0.000 claims description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 claims description 2
- 229940105329 carboxymethylcellulose Drugs 0.000 claims description 2
- 239000000665 guar gum Substances 0.000 claims description 2
- 235000010417 guar gum Nutrition 0.000 claims description 2
- 229960002154 guar gum Drugs 0.000 claims description 2
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 claims description 2
- 229940071826 hydroxyethyl cellulose Drugs 0.000 claims description 2
- 235000019426 modified starch Nutrition 0.000 claims description 2
- 239000000178 monomer Substances 0.000 claims description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims description 2
- AOHJOMMDDJHIJH-UHFFFAOYSA-N propylenediamine Chemical compound CC(N)CN AOHJOMMDDJHIJH-UHFFFAOYSA-N 0.000 claims description 2
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 claims description 2
- 229910021653 sulphate ion Inorganic materials 0.000 claims description 2
- NURQLCJSMXZBPC-UHFFFAOYSA-N 3,4-dimethylpyridine Chemical compound CC1=CC=NC=C1C NURQLCJSMXZBPC-UHFFFAOYSA-N 0.000 claims 2
- 229920003170 water-soluble synthetic polymer Polymers 0.000 claims 2
- 229920006322 acrylamide copolymer Polymers 0.000 claims 1
- 229920003090 carboxymethyl hydroxyethyl cellulose Polymers 0.000 claims 1
- 239000003795 chemical substances by application Substances 0.000 claims 1
- 150000007524 organic acids Chemical class 0.000 claims 1
- 239000000243 solution Substances 0.000 description 22
- 239000000499 gel Substances 0.000 description 15
- 229920000642 polymer Polymers 0.000 description 9
- 239000003921 oil Substances 0.000 description 8
- 238000000605 extraction Methods 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 239000003208 petroleum Substances 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 238000004132 cross linking Methods 0.000 description 4
- 230000003111 delayed effect Effects 0.000 description 4
- 230000007062 hydrolysis Effects 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical class [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 3
- 239000010779 crude oil Substances 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- JYYNAJVZFGKDEQ-UHFFFAOYSA-N 2,4-Dimethylpyridine Chemical compound CC1=CC=NC(C)=C1 JYYNAJVZFGKDEQ-UHFFFAOYSA-N 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000013043 chemical agent Substances 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 150000004676 glycans Chemical class 0.000 description 2
- 150000007529 inorganic bases Chemical class 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 229920001282 polysaccharide Polymers 0.000 description 2
- 239000005017 polysaccharide Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229920001059 synthetic polymer Polymers 0.000 description 2
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 description 2
- 229920003169 water-soluble polymer Polymers 0.000 description 2
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- KRKNYBCHXYNGOX-UHFFFAOYSA-K Citrate Chemical compound [O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O KRKNYBCHXYNGOX-UHFFFAOYSA-K 0.000 description 1
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 description 1
- 229920002153 Hydroxypropyl cellulose Polymers 0.000 description 1
- FEWJPZIEWOKRBE-JCYAYHJZSA-L L-tartrate(2-) Chemical compound [O-]C(=O)[C@H](O)[C@@H](O)C([O-])=O FEWJPZIEWOKRBE-JCYAYHJZSA-L 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-L Malonate Chemical compound [O-]C(=O)CC([O-])=O OFOBLEOULBTSOW-UHFFFAOYSA-L 0.000 description 1
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 159000000032 aromatic acids Chemical class 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 229940092714 benzenesulfonic acid Drugs 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 125000002843 carboxylic acid group Chemical group 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000009918 complex formation Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000001863 hydroxypropyl cellulose Substances 0.000 description 1
- 235000010977 hydroxypropyl cellulose Nutrition 0.000 description 1
- 229940071676 hydroxypropylcellulose Drugs 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000004391 petroleum recovery Methods 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 230000000979 retarding effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229940095064 tartrate Drugs 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/84—Compositions based on water or polar solvents
- C09K8/86—Compositions based on water or polar solvents containing organic compounds
- C09K8/88—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
- C09K8/887—Compositions based on water or polar solvents containing organic compounds macromolecular compounds containing cross-linking agents
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
- C09K8/504—Compositions based on water or polar solvents
- C09K8/506—Compositions based on water or polar solvents containing organic compounds
- C09K8/508—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
- C09K8/512—Compositions based on water or polar solvents containing organic compounds macromolecular compounds containing cross-linking agents
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Colloid Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Medicinal Preparation (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Description
Foreliggende oppfinnelse vedrører en gelerbar vandig blanding som er istand til å redusere permeabiliteten av høypermeabi-litetssoner i et oljereservoar. Oppfinnelsen vedrører også en fremgangsmåte for å redusere permeabiliteten av en høy-permeabilitetssone i et oljereservoar. Disse og andre trekk ved oppfinnelsen fremgår av patentkravene. The present invention relates to a gelable aqueous mixture which is able to reduce the permeability of high permeability zones in an oil reservoir. The invention also relates to a method for reducing the permeability of a high-permeability zone in an oil reservoir. These and other features of the invention appear in the patent claims.
De såkalte primære utvinningsmetoder for petroleum tar i bruk reservoarets naturlige energi eller mekaniske midler for å produsere petroleum fra brønnene, men disse metoder er imidlertid kjent til å gi kun delvis ekstraksjon av råoljen inneholdt i reservoaret. For å øke mengden ekstraherbar petroleum, anvendes derfor vanligvis sekundære utvinnings-teknikker som i alt vesentlig består av at det i reservoaret innføres et fluid, generelt vann eller en vandig polymer-løsning, som leder råoljen gjennom porene, i fjellet til ekstraksjonsbrønnen. Da mange reservoarer imidlertid utgjøres av flere stentyper med forskjellig permeabilitet, har det injiserte fluid en tendens til å ledes gjennom soner med større permeabilitet, uten gjennomstrømning eller med bare delvis gjennomstrømning av sonene med mindre permeabilitet. Dette kan i stor grad begrense utvinning av petroleum fra reservoaret. The so-called primary extraction methods for petroleum use the reservoir's natural energy or mechanical means to produce petroleum from the wells, but these methods are, however, known to provide only partial extraction of the crude oil contained in the reservoir. In order to increase the amount of extractable petroleum, secondary extraction techniques are therefore usually used which essentially consist of introducing a fluid, generally water or an aqueous polymer solution, into the reservoir, which leads the crude oil through the pores, into the rock to the extraction well. However, since many reservoirs are made up of several rock types with different permeability, the injected fluid tends to be led through zones with greater permeability, without flow through or with only partial flow through the zones with lower permeability. This can greatly limit the extraction of petroleum from the reservoir.
For å løse dette problem, kan man anvende en av teknikkene for økt petroleumsutvinning basert på den i det minste delvise okklusjon av høypermeabilitetssoner. Dette gjennomføres ved at en gelerbar vandig petroleumsløsning innføres i reservoaret gjennom en eller flere brønner til å danne polymergeler in situ. På denne måte er det mulig å lede fluidstrømmen som deretter innføres i reservoaret mot områder med mindre permeabilitet og således utvinne råoljen inneholdt i disse. To solve this problem, one can apply one of the techniques for increased petroleum recovery based on the at least partial occlusion of high permeability zones. This is carried out by introducing a gelable aqueous petroleum solution into the reservoir through one or more wells to form polymer gels in situ. In this way, it is possible to direct the fluid flow which is then introduced into the reservoir towards areas with less permeability and thus extract the crude oil contained in these.
De gelerbare oppløsninger som anvendes til dette formål er normalt en vandig oppløsning av en vannoppløselig polymer som et polyakrylamid, et delvis hydrolysert polyakrylamid eller en biopolymer slik som xantangummi, som kan tverrbinde under innvirkning av et ion av et polyvalent metall, normalt Cr(III) eller Al(III). Da sonene som skal okkluderes kan være svært omfattende og/eller i en større eller mindre avstand fra injeksjonsbrønnen, må geleringsoppløsningen dessuten ha forsinket gelering for å tillate at oppløsningen når høypermeabilitetssonene i reservoaret og fyller dem fullstendig . The gelable solutions used for this purpose are normally an aqueous solution of a water-soluble polymer such as a polyacrylamide, a partially hydrolysed polyacrylamide or a biopolymer such as xanthan gum, which can cross-link under the influence of an ion of a polyvalent metal, normally Cr(III) or Al(III). As the zones to be occluded may be very extensive and/or at a greater or lesser distance from the injection well, the gelling solution must also have delayed gelation to allow the solution to reach the high permeability zones in the reservoir and fill them completely.
Det tekniske problem med forsinket gelering er blitt møtt på forskjellige måter. I en kjent metode som f.eks. er beskrevet i US patent 3.785.437 injiseres således en vandig oppløsning inneholdende den fornettbare polymer og et heksavalent krom-salt, som i seg selv ikke er istand til å tverrbinde~ polymeren, inn i reservoaret. Krom reduseres deretter til den trivalente tilstand ved lav reduksjonshastighet ved hjelp av et reduksjonsmiddel (som tiourea eller bisulfitt) enten inneholdt i den gelerbare løsning eller injisert i reservoaret i form av en vandig oppløsning, etter injeksjon av den gelerbare oppløsning, for å indusere gelering som skyldes blanding av injiserte oppløsninger i reservoarene. Denne Cr(VI)/reduksjonsmiddelmetode har den fordel at det er mulig å oppnå gelering med en en-komponent gelerbar blanding, men den har ulempen med giftighet av heksavalent krom og følgelig dennes innvirkning på omgivelsene. The technical problem of delayed gelation has been met in various ways. In a known method such as e.g. is described in US patent 3,785,437, thus an aqueous solution containing the crosslinkable polymer and a hexavalent chromium salt, which in itself is not capable of crosslinking the polymer, is injected into the reservoir. Chromium is then reduced to the trivalent state at a low reduction rate by a reducing agent (such as thiourea or bisulphite) either contained in the gelable solution or injected into the reservoir in the form of an aqueous solution, after injection of the gelable solution, to induce gelation which is due to mixing of injected solutions in the reservoirs. This Cr(VI)/reducing agent method has the advantage that it is possible to achieve gelation with a one-component gelable mixture, but it has the disadvantage of toxicity of hexavalent chromium and consequently its impact on the environment.
Når det gjelder sekvensiell injeksjon omfatter ulempene ufullstendig blanding av de injiserte oppløsninger, slik at gelen kun dannes i deres grenseflater, og den er derfor tynn og svekkes lett. US patent 3.762.476 beskriver en gelerbar blanding som kan anvendes for å avhjelpe permeabilitet i et undergrunnsreservoar, omfattende en polymer som kan tverr-bindes og et tverrbindingsmiddel i form av et ion av et polyvalent metall som er kompleksdannet med bestemte anioner med sekvestrerende og forsinkende egenskaper. I overensstemmelse med beskrivelsen i dette patent, injiseres oppløsningen av det kompleksdannede tverrbindingsmiddel inn i reservoaret etter injeksjon av den polymere vandige oppløsning, og således overvinnes ikke de ovennevnte ulemper som er forbundet med sekvensiell injeksjon. When it comes to sequential injection, the disadvantages include incomplete mixing of the injected solutions, so that the gel is only formed at their interfaces, and it is therefore thin and weakens easily. US patent 3,762,476 describes a gelable mixture that can be used to remedy permeability in an underground reservoir, comprising a polymer that can be cross-linked and a cross-linking agent in the form of an ion of a polyvalent metal that is complexed with certain anions with sequestering and retarding properties. In accordance with the description in this patent, the solution of the complexed cross-linking agent is injected into the reservoir after injection of the polymeric aqueous solution, and thus the above disadvantages associated with sequential injection are not overcome.
US patent 4.683.949 beskriver gelerbare vandige blandinger som kan anvendes i metoder for økt utvinning av petroleum og som inneholder et vannoppløselig polyakrylamid og et tverrbindingsmiddel i form av et Cr(III)-kompleks med et karboksylat-ion, og mere spesielt et alifatisk monokarboksylsyreion, særlig et acetation. Ved anvendelse av denne blanding unngås problemene i forbindelse med sekvensiell injeksjon, men den oppnådde forsinkede tverrbinding er imidlertid beskjeden. Følgelig er disse blandinger upassende for anbringelse av gelen i dype områder i reservoaret, noe som normalt er ønskelig i praksis. US patent 4,683,949 describes gelable aqueous mixtures which can be used in methods for increased extraction of petroleum and which contain a water-soluble polyacrylamide and a cross-linking agent in the form of a Cr(III) complex with a carboxylate ion, and more particularly an aliphatic monocarboxylic acid ion , especially an acetate. By using this mixture, the problems associated with sequential injection are avoided, but the delayed cross-linking achieved is however modest. Consequently, these mixtures are unsuitable for placing the gel in deep areas of the reservoir, which is normally desirable in practice.
Man har nå funnet at vandige oppløsninger inneholdende en organisk polymer som kan tverrbinde og et Cr(III)-ion som tverrbindingsmiddel gelerer i en takt som er avhengig av pH-verdien innen pH-området for gelering. Det skal imidlertid bemerkes at når de nevnte gelerbare oppløsninger inj iseres inn i et oljereservoar, gjennomgår de pH-forandringer på grunn av hydrolyse, blanding med reservoarvann og/eller den kjemiske natur av fjellet som de kommer i kontakt med, og den totale effekt er for tidlig gelering. Dette gir et ytterligere usikkerhetsmoment med hensyn til å anslå geleringshastigheten og således den korrekte plassering av gelen i reservoaret. It has now been found that aqueous solutions containing an organic polymer that can cross-link and a Cr(III) ion as cross-linking agent gel at a rate that depends on the pH value within the pH range for gelation. However, it should be noted that when the aforementioned gellable solutions are injected into an oil reservoir, they undergo pH changes due to hydrolysis, mixing with reservoir water and/or the chemical nature of the rock with which they come into contact, and the overall effect is premature gelation. This gives a further element of uncertainty with regard to estimating the gelation rate and thus the correct location of the gel in the reservoir.
Det vil derfor være ønskelig å ha gelerbare vandige oppløsninger tilgjengelige som har en geleringstid som kan kontrolleres innen et utstrakt område og som er uavhengig av eller i alt vesentlig uavhengig av egenskapene til det behandlede reservoar. It would therefore be desirable to have gelable aqueous solutions available which have a gelation time which can be controlled within an extended area and which is independent of or substantially independent of the properties of the treated reservoir.
Dette er blitt mulig ved hjelp av de gelerbare blandinger i henhold til oppfinnelsen, som inneholder spesielle buffere i tillegg til en polymer som kan tverrbinde og tverrbindingsmidlet. This has become possible with the help of the gelable mixtures according to the invention, which contain special buffers in addition to a polymer which can cross-link and the cross-linking agent.
I overensstemmelse med det ovennevnte, er et aspekt av den foreliggende oppfinnelse en gelerbar vandig blanding som er istand til å redusere permeabiliteten av høypermeabilitets-soner i et oljereservoar, og som er i form av en vandig oppløsning omfattende: - a) en vannoppløselig organisk polymer som kan tverrbinde under innvirkning av et polyvalent metallion som tverrbindingsmiddel , In accordance with the above, one aspect of the present invention is a gellable aqueous mixture capable of reducing the permeability of high permeability zones in an oil reservoir, and which is in the form of an aqueous solution comprising: - a) a water-soluble organic polymer which can cross-link under the influence of a polyvalent metal ion as a cross-linking agent,
- b et Cr(III)-ion som tverrbindingsmiddel, og - b a Cr(III) ion as a cross-linking agent, and
- c) en buffer uten eller i alt vesentlig uten ligandegenskaper overfor tverrbindingsmidlet og som er valgt fra organiske baser og karboksyl- eller sulfonaromatiske organiske syrer med en pKa mellom 0,5 og 8, idet komponent a) er tilstede i en mengde mellom 1000 og 50.000 ppm, komponent b) er tilstede i en mengde mellom 10 og 5000 ppm, vektforholdet mellom komponent a) og komponent b) varierer fra 1:1 til 1000:1, komponent c) er tilstede i en konsentrasjon mellom 0,005 M og 0,5 M, og pH i blandingen justeres til en verdi innen området fra 2 til 7. - c) a buffer without or substantially without ligand properties towards the cross-linking agent and which is selected from organic bases and carboxylic or sulphonic aromatic organic acids with a pKa between 0.5 and 8, component a) being present in an amount between 1000 and 50,000 ppm, component b) is present in an amount between 10 and 5000 ppm, the weight ratio between component a) and component b) varies from 1:1 to 1000:1, component c) is present in a concentration between 0.005 M and 0, 5 M, and the pH of the mixture is adjusted to a value in the range from 2 to 7.
I den foreliggende beskrivelse betyr ppm vektdeler pr million. Vannoppløselige polymerer som kan anvendes i blandingene i overensstemmelse med oppfinnelsen er vannoppløselige biopolymerer og syntetiske polymerer med høy molekylvekt omfattende karboksylsyregrupper og som er istand til å gelere i nærvær av tverrbindingsmidlet innen pH-området for tverrbinding (pH mellom 2 og 7). Biopolymerene omfatter polysakkarider og modifiserte polysakkarider. Eksempler på biopolymerer er xantangummi, guargummi, karboksymetylcellulose, hydroksyetylcellulose, hydroksypropylcellulose og modifiserte stivelser. Syntetiske polymerer som kan anvendes for dette formål omfatter akrylamidpolymerer slik som polyakrylamid, delvis hydrolysert polyakrylamid og kopolymerene av akrylamid med en eller flere kopolymeriserbare monomerer. Den vektmidlere molekylvekt for disse polymerer og kopolymerer varierer generelt fra 100.000 til 20.000.000 og deres konsentrasjon i blandingen varierer fra 1000 til 50.000 ppm. In the present description, ppm means parts by weight per million. Water-soluble polymers that can be used in the mixtures in accordance with the invention are water-soluble biopolymers and synthetic polymers with a high molecular weight comprising carboxylic acid groups and which are able to gel in the presence of the cross-linking agent within the pH range for cross-linking (pH between 2 and 7). The biopolymers include polysaccharides and modified polysaccharides. Examples of biopolymers are xanthan gum, guar gum, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and modified starches. Synthetic polymers that can be used for this purpose include acrylamide polymers such as polyacrylamide, partially hydrolyzed polyacrylamide and the copolymers of acrylamide with one or more copolymerizable monomers. The weight average molecular weight of these polymers and copolymers generally ranges from 100,000 to 20,000,000 and their concentration in the mixture ranges from 1,000 to 50,000 ppm.
I en foretrukket utførelsesform anvendes akrylpolymerer eller deres delvise hydrolyseprodukter, med en vektmidlere molekylvekt mellom 2 00.000 og 12.000.000, i en konsentrasjon som varierer fra 4000 til 30.000 ppm. In a preferred embodiment, acrylic polymers or their partial hydrolysis products are used, with a weight average molecular weight between 200,000 and 12,000,000, in a concentration varying from 4,000 to 30,000 ppm.
Tverrbindingsmidlet som kan anvendes i blandingene i overensstemmelse med oppfinnelsen er Cr(III)-ionet og derfor kan de vannoppløselige organiske salter av dette metall som kloridet, nitratet eller sulfatet anvendes. Konsentrasjonen av tverrbindingsmidlet i blandingen, uttrykt som metall, varierer mellom 10 og 5000 ppm og er foretrukket mellom 25 og 500 ppm. Vektforholdet mellom den vannoppløselige organiske polymer og tverrbindingsmidlet holdes mellom 1:1 og 1000:1, og er foretrukket mellom 5:1 og 500:1. The cross-linking agent which can be used in the mixtures in accordance with the invention is the Cr(III) ion and therefore the water-soluble organic salts of this metal such as the chloride, nitrate or sulphate can be used. The concentration of the cross-linking agent in the mixture, expressed as metal, varies between 10 and 5000 ppm and is preferably between 25 and 500 ppm. The weight ratio between the water-soluble organic polymer and the cross-linking agent is kept between 1:1 and 1000:1, and is preferably between 5:1 and 500:1.
Bufferne som anvendes er organiske baser eller karboksyl-eller sulfonaromatiske syrer med pKa mellom 0,5 og 8 "og uten eller i alt vesentlig uten ligandegenskaper overfor tverrbindingsmidlet. Eksempler på slike organiske baser er alifatiske eller aromatiske organiske aminer slik som anilin, 2-bromanilin, 3-bromanilin, 4-kloranilin, 4-nitroanilin, difenylamin og propan-1,2-diamin. Andre eksempler på organiske baser er heterocykliske organiske forbindelser inneholdende minst et nitrogenheteroatom i ringen, som tiazol, 2-aminotiazol, piperazin, imidazol, benzimidazol, kinolin, isokinolin, piperidin, pyridin, 2,4-lutidin, 3-klorpyridin og o-toluidin. Eksempler på karboksyl- eller sulfonaromatiske syrer er benzosyre, 2-nitrobenzosyre, 2-klorbenzosyre og benzensulfonsyre. En bufferkonsentrasjon mellom 0,005 M og 0,5 M og foretrukket mellom 0,0075 M og 0,1 M opprettholdes passende i blandingen i overensstemmelse med oppfinnelsen. The buffers used are organic bases or carboxylic or sulphonic aromatic acids with a pKa between 0.5 and 8" and without or essentially without ligand properties towards the cross-linking agent. Examples of such organic bases are aliphatic or aromatic organic amines such as aniline, 2-bromoaniline , 3-bromoaniline, 4-chloroaniline, 4-nitroaniline, diphenylamine and propane-1,2-diamine. Other examples of organic bases are heterocyclic organic compounds containing at least one nitrogen heteroatom in the ring, such as thiazole, 2-aminothiazole, piperazine, imidazole, benzimidazole, quinoline, isoquinoline, piperidine, pyridine, 2,4-lutidine, 3-chloropyridine and o-toluidine. Examples of carboxylic or sulphonaromatic acids are benzoic acid, 2-nitrobenzoic acid, 2-chlorobenzoic acid and benzenesulphonic acid. A buffer concentration between 0.005 M and 0.5 M and preferably between 0.0075 M and 0.1 M is suitably maintained in the mixture in accordance with the invention.
I tillegg har blandingen i henhold til oppfinnelsen en pH innen geleringsområdet for blandingen, som generelt kan variere fra 2 til 7, idet den valgte verdi avhenger av ønsket geleringstid. Følgelig kan pH-verdien i blandingen justeres ved tilsetning av en mineralsyre som saltsyre eller perklorsyre, eller en uorganisk base som natriumhydroksyd, om nødvendig eller om ønskelig. Det skal bemerkes at ved pH-verdier over 7, dannes kolloidal Cr(OH)3*3H20 som er inaktiv for geleringsformål og det er således ikke mulig å operere ved slike pH-verdier. In addition, the mixture according to the invention has a pH within the gelation range of the mixture, which can generally vary from 2 to 7, the selected value depending on the desired gelation time. Accordingly, the pH of the mixture can be adjusted by adding a mineral acid such as hydrochloric acid or perchloric acid, or an inorganic base such as sodium hydroxide, if necessary or desired. It should be noted that at pH values above 7, colloidal Cr(OH)3*3H20 is formed which is inactive for gelation purposes and it is thus not possible to operate at such pH values.
Anvendelse av bufferen gjør det mulig å holde pH i den gelerbare oppløsning konstant i en forlenget tidsperiode, eller i det minste nedsette variasjonen i pH som indusert ved naturen til det behandlede reservoar betraktelig for å tillate god kontroll av geleringstiden i alle tilfeller. Application of the buffer makes it possible to keep the pH of the gelable solution constant for an extended period of time, or at least to reduce the variation in pH as induced by the nature of the treated reservoir considerably to allow good control of the gelation time in all cases.
Det er generelt viktig å opprettholde en foretrukket pH-verdi i lange tidsperioder i omgivelser hvor det er naturlig for vandige geler eller gelerbare oppløsninger å omdanne til dem med mindre ønskelig pH. En slik pH-forandring kan f.eks. skje ved høy temperatur hvor kjemiske forandringer som hydrolyse av polymeren fører til en uønsket pH-forandring. I andre tilfeller kan en uønsket pH-forandring skje ved at gelen er i kontakt med andre vandige oppløsninger eller kjemiske midler. Den uønskede pH-forandring kan resultere i at gelens stabilitet over en lengre tidsperiode nedsettes, eller i en forandring i geleringshastigheten. Dette sistnevnte problem fører til mye usikkerhet, f.eks. i forsøk på å plassere en gelerbar blanding riktig i en bestemt posisjon i et oljereservoar for profilmodifikasjon. I andre tilfeller, kan pH velges for å redusere korrosjon der hvor den gelerbare oppløsning kommer i kontakt med metallutstyr, eller for å produsere en gelerbar oppløsning og en endelig gel som ikke er skadelig dersom den kommer i kontakt med menneskets hud eller øyne. It is generally important to maintain a preferred pH value for long periods of time in environments where it is natural for aqueous gels or gelable solutions to convert to those with less desirable pH. Such a pH change can e.g. happen at high temperature where chemical changes such as hydrolysis of the polymer lead to an undesirable pH change. In other cases, an unwanted pH change can occur when the gel is in contact with other aqueous solutions or chemical agents. The unwanted pH change can result in the stability of the gel being reduced over a longer period of time, or in a change in the gelation rate. This latter problem leads to a lot of uncertainty, e.g. in an attempt to properly place a gellable mixture in a specific position in an oil reservoir for profile modification. In other cases, the pH may be selected to reduce corrosion where the gelable solution contacts metal equipment, or to produce a gelable solution and a final gel that is not harmful if it comes into contact with human skin or eyes.
I henhold til et ytterligere aspekt tilveiebringer den foreliggende oppfinnelse en fremgangsmåte for å redusere permeabiliteten av en høypermeabilitetssone i et oljereservoar, og som er kjennetegnet ved at den omfatter trinnene med: - fremstilling av en gelerbar blanding, over bakken og under kontrollerte betingelser, - injeksjon av denne fremstilte blanding inn i oljereservoaret gjennom minst en brønn, - transportering av blandingen gjennom reservoaret inntil den når og i alt vesentlig fyller høypermeabilitetssonen som skal behandles, og - gelering av blandingen in situ med følgende nedsettelse av permeabiliteten i ovennevnte høypermeabilitetssone. According to a further aspect, the present invention provides a method for reducing the permeability of a high permeability zone in an oil reservoir, and which is characterized in that it comprises the steps of: - preparation of a gelable mixture, above ground and under controlled conditions, - injection of this produced mixture into the oil reservoir through at least one well, - transporting the mixture through the reservoir until it reaches and essentially fills the high permeability zone to be treated, and - gelation of the mixture in situ with the following reduction of permeability in the above-mentioned high permeability zone.
Den gelerbare vandige blanding fremstilles ved enkel blanding av bestanddelene, idet man opererer ved omgivelsestemperatur. I hvilken rekkefølge bestanddelene tilsettes er ikke kritisk, men i en foretrukket utførelsesform fremstilles imidlertid først en vandig oppløsning av den vannoppløselige organiske polymer og en buffer, idet pH justeres ved hjelp av en mineralsyre eller uorganisk base. En vandig oppløsning av tverrbindingsmidlet fremstilles separat. De to fremstilte oppløsninger blandes deretter sammen. The gelable aqueous mixture is prepared by simple mixing of the components, operating at ambient temperature. The order in which the components are added is not critical, but in a preferred embodiment, however, an aqueous solution of the water-soluble organic polymer and a buffer is first prepared, the pH being adjusted using a mineral acid or inorganic base. An aqueous solution of the cross-linking agent is prepared separately. The two prepared solutions are then mixed together.
Andre områder hvor blandingen i henhold til oppfinnelsen kan anvendes omfatter belegg, skumplast og fremstilling av korroderende filmer for metaller. Other areas where the mixture according to the invention can be used include coatings, foam plastics and the production of corrosive films for metals.
Som man vil se fra utførelseseksemplene i det følgende, vil anvendelse av de ovennevnte buffere gjøre de gelerbare vandige blandinger istand til å gjennomgå en forsinket gelering som kan justeres med hensyn til geleringstid, som en funksjon av pH innen et utstrakt område. Denne geleringstid er likeledes upåvirkelig av eller høyst lett påvirkelig av naturen av det behandlede reservoar. Dessuten forekommer gelering både ved omgivelsestemperatur og ved høyere temperaturer, med dannelse av stabile, kompakte geler. Det er derfor mulig å fremstille gelerbare vandige oppløsninger som er passende for de svært ulike forhold som finnes i et oljereservoar. As will be seen from the embodiments below, use of the above buffers will enable the gelable aqueous mixtures to undergo a delayed gelation that can be adjusted with respect to gelation time as a function of pH within a wide range. This gelation time is likewise unaffected by or very easily influenced by the nature of the treated reservoir. Furthermore, gelation occurs both at ambient temperature and at higher temperatures, with the formation of stable, compact gels. It is therefore possible to produce gelable aqueous solutions which are suitable for the very different conditions found in an oil reservoir.
I de etterfølgende utførelseseksempler beskrives oppfinnelsen ytterligere. The invention is further described in the following exemplary embodiments.
EKSEMPEL 1 EXAMPLE 1
Vandige oppløsninger fremstilles i destillert vann inneholdende 8.000 ppm av et kommersielt polyakrylamid (1 % hydrolyse, vektmidlere molekylvekt 5.000.000 - 6.000.000), Aqueous solutions are prepared in distilled water containing 8,000 ppm of a commercial polyacrylamide (1% hydrolysis, weight average molecular weight 5,000,000 - 6,000,000),
50 ppm Cr(III) tilført i form av Cr(III)-klorid eller -nitrat, en buffer og perklorsyre i den mengde som er nødvendig for å justere pH til ønsket verdi. Tiden (i døgn) som kreves for at oppløsningene gelerer fullstendig ved en temperatur på 25 og 60°C er angitt. De oppnådde resultater er gitt i den etter-f ø1gende tabe11. 50 ppm Cr(III) added in the form of Cr(III) chloride or nitrate, a buffer and perchloric acid in the amount necessary to adjust the pH to the desired value. The time (in days) required for the solutions to gel completely at a temperature of 25 and 60°C is indicated. The results obtained are given in the following table11.
pH i blandingene ble undersøkt med jevne mellomrom med en mikroelektrode, og man fant at pH varierte med mindre enn 0,2 enheter over en periode på 46 døgn. The pH of the mixtures was examined at regular intervals with a microelectrode, and it was found that the pH varied by less than 0.2 units over a period of 46 days.
EKSEMPEL 2 EXAMPLE 2
Man fulgte prosedyren i eksempel 1 med fremstilling av gelerbare blandinger inneholdende buffere i form av karboksyl- og sulfonaromatiske organiske syrer i en konsentrasjon på 0,0075 M, med unntak av benzensulfonsyre, hvis konsentrasjon var 0,01 M. Forsøksresultatene er gitt i den etterfølgende tabell. The procedure in example 1 was followed with the preparation of gelable mixtures containing buffers in the form of carboxylic and sulfonic aromatic organic acids in a concentration of 0.0075 M, with the exception of benzenesulfonic acid, whose concentration was 0.01 M. The test results are given in the following table.
Resultatene fra forsøkseksemplene 1 og 2 som er gjennomført ved 60°C er gjengitt på kurven i figuren hvor den horisontale akse indikerer pH i den gelerbare oppløsning og den vertikale akse uttrykker geleringstiden i døgn. The results from test examples 1 and 2, which were carried out at 60°C, are reproduced on the curve in the figure, where the horizontal axis indicates the pH of the gelable solution and the vertical axis expresses the gelation time in 24 hours.
EKSEMPEL 3 EXAMPLE 3
Gelerbare vandige oppløsninger med regulert pH fremstilles inneholdende 8.000 ppm av polyakrylamidet i eks. 1, 50 ppm Cr(III) og en buffer. Disse oppløsninger geleres ved 60°C. Forsøksdetaljene er gitt i den etterfølgende tabell. Gelable aqueous solutions with regulated pH are prepared containing 8,000 ppm of the polyacrylamide in ex. 1, 50 ppm Cr(III) and a buffer. These solutions gel at 60°C. The trial details are given in the following table.
EKSEMPEL 4 EXAMPLE 4
Gelerbare vandige oppløsninger med regulert pH ble fremstilt ifølge prosedyren i eks. 1. Gelable aqueous solutions with regulated pH were prepared according to the procedure in ex. 1.
Disse oppløsninger geleres ved 90°C og forsøksresultatene er gitt i etterfølgende tabell. These solutions are gelled at 90°C and the test results are given in the following table.
EKSEMPEL 5 (sammenligning) EXAMPLE 5 (Comparison)
Gelerbare vandige oppløsninger med regulert pH fremstilles inneholdende 8.000 ppm av polyakrylamidet i eks. 1, 50 ppm Cr(III) og en buffer med bindingsegenskaper overfor Cr(III). Disse oppløsninger geleres ved 25 og 60°C. Forsøksdetaljer er gitt i etterfølgende tabell. Gelable aqueous solutions with regulated pH are prepared containing 8,000 ppm of the polyacrylamide in ex. 1, 50 ppm Cr(III) and a buffer with binding properties towards Cr(III). These solutions gel at 25 and 60°C. Test details are given in the following table.
Som det fremgår fra eks. 5, interfererer de tradisjonelle bufferne oksalat, citrat, acetat, tartrat og malonat med gelering, idet de enten blokkerer den fullstendig eller gir svake geler. Et aspekt av den foreliggende oppfinnelse omfatter identifisering av forskjellige klasser av kjemiske forbindelser som virker effektivt som buffere uten at de interfererer med geleringskjemien. Uten at man ønsker å fremsette en spesiell teori, er det foreslått at mangel på gunstige resultater i forbindelse med oppløsninger som er bufret med de tradisjonelle buffere kan skyldes kompleks-dannelsen av disse kjemiske midler med tverrbindings-metallionet, slik at ionets reaksjon med polymeren blokkeres. Til støtte for denne mekanisme skal det bemerkes at de effektive bufferne som anvendes i blandingene i henhold til oppfinnelsen er i alt vesentlig uten ligandegenskaper overfor Cr(III), og dette betraktes som en vesentlig betingelse for enhver effektiv buffer. As can be seen from e.g. 5, the traditional buffers oxalate, citrate, acetate, tartrate and malonate interfere with gelation, either blocking it completely or producing weak gels. One aspect of the present invention involves the identification of various classes of chemical compounds that act effectively as buffers without interfering with gelation chemistry. Without wishing to advance a particular theory, it is proposed that the lack of favorable results in connection with solutions buffered with the traditional buffers may be due to the complex formation of these chemical agents with the cross-linking metal ion, so that the ion's reaction with the polymer is blocked . In support of this mechanism, it should be noted that the effective buffers used in the mixtures according to the invention are essentially without ligand properties towards Cr(III), and this is considered an essential condition for any effective buffer.
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| IT8919969A IT1229218B (en) | 1989-03-31 | 1989-03-31 | GELIFICABLE BUFFERED WATER COMPOSITION AND ITS USE IN OIL ASSISTED RECOVERY PROCEDURES. |
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| US5219476A (en) * | 1989-03-31 | 1993-06-15 | Eniricerche S.P.A. | Gellable aqueous composition and its use in enhanced petroleum recovery |
| IT1245383B (en) * | 1991-03-28 | 1994-09-20 | Eniricerche Spa | GELIFIABLE WATER COMPOSITION WITH DELAYED GELIFICATION TIME |
| US5342543A (en) * | 1991-05-28 | 1994-08-30 | Data Medical Associates, Inc. | Neutralizing absorbent for acids and bases |
| IT1264383B1 (en) * | 1993-05-07 | 1996-09-23 | Eniricerche Spa | FLUIDIFIED AQUEOUS DRILLING MUD WITH ZIRCONIUM AND ALUMINUM CONPLESSES |
| US6524653B1 (en) | 2000-11-01 | 2003-02-25 | Niponi, Llc | Cellulose-based fire retardant composition |
| JP4446233B2 (en) * | 2004-03-03 | 2010-04-07 | ディップソール株式会社 | Covalent friction coefficient reducing agent for trivalent chromate treatment solution, trivalent chromate treatment solution and production method thereof, trivalent chromate coating with reduced overall friction coefficient and production method thereof |
| US20070187098A1 (en) * | 2006-02-14 | 2007-08-16 | Putzig Donald E | Permeable zone and leak plugging using cross-linking composition comprising delay agent |
| US7732382B2 (en) * | 2006-02-14 | 2010-06-08 | E.I. Du Pont De Nemours And Company | Cross-linking composition and method of use |
| US20070187102A1 (en) * | 2006-02-14 | 2007-08-16 | Putzig Donald E | Hydraulic fracturing methods using cross-linking composition comprising delay agent |
| US10562984B2 (en) | 2013-08-30 | 2020-02-18 | Dai-Ichi Kogyo Seiyaku Co., Ltd. | Crude oil recovery additive |
| US20170073570A1 (en) * | 2014-03-03 | 2017-03-16 | Dai-Ichi Kogyo Seiyaku Co., Ltd. | Device for pressing in cellulose fiber nano-dispersion, method for pressing in cellulose fiber nano-dispersion using same, and hydrocarbon production method |
| CN108350347A (en) * | 2015-09-17 | 2018-07-31 | 沙特阿拉伯石油公司 | Chemical imbibition of the gel containing surfactant to crack Carbonate Reservoir |
| US11274243B2 (en) | 2018-06-08 | 2022-03-15 | Sunita Hydrocolloids Inc. | Friction reducers, fracturing fluid compositions and uses thereof |
| US12054669B2 (en) | 2018-06-08 | 2024-08-06 | Sunita Hydrocolloids Inc. | Friction reducers, fluid compositions and uses thereof |
| US11746282B2 (en) | 2018-06-08 | 2023-09-05 | Sunita Hydrocolloids Inc. | Friction reducers, fracturing fluid compositions and uses thereof |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3615794A (en) * | 1968-05-20 | 1971-10-26 | Dow Chemical Co | Sealing composition and method |
| US4552217A (en) * | 1984-07-09 | 1985-11-12 | Phillips Petroleum Company | Microbiocidal anionic sequesterants with polyvalent metal cations for permeability correction process |
| US4606407A (en) * | 1984-11-29 | 1986-08-19 | Mobil Oil Corporation | Programmed gelation of polymers for oil reservoir permeability control |
-
1989
- 1989-03-31 IT IT8919969A patent/IT1229218B/en active
-
1990
- 1990-03-27 DK DK90200726.9T patent/DK0390281T3/en active
- 1990-03-27 EP EP90200726A patent/EP0390281B1/en not_active Expired - Lifetime
- 1990-03-27 ES ES199090200726T patent/ES2038034T3/en not_active Expired - Lifetime
- 1990-03-27 US US07/499,681 patent/US5100932A/en not_active Expired - Lifetime
- 1990-03-29 NO NO901443A patent/NO179187C/en unknown
- 1990-03-30 MX MX020136A patent/MX171743B/en unknown
- 1990-03-30 CA CA002013469A patent/CA2013469C/en not_active Expired - Fee Related
- 1990-03-30 BR BR909001655A patent/BR9001655A/en not_active IP Right Cessation
- 1990-03-30 JP JP2081448A patent/JPH02272191A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| IT8919969A0 (en) | 1989-03-31 |
| NO901443L (en) | 1990-10-01 |
| NO179187C (en) | 1996-08-21 |
| BR9001655A (en) | 1991-05-14 |
| CA2013469A1 (en) | 1990-09-30 |
| US5100932A (en) | 1992-03-31 |
| ES2038034T3 (en) | 1993-07-01 |
| DK0390281T3 (en) | 1993-01-25 |
| EP0390281A1 (en) | 1990-10-03 |
| IT1229218B (en) | 1991-07-26 |
| CA2013469C (en) | 1998-08-11 |
| JPH02272191A (en) | 1990-11-06 |
| NO901443D0 (en) | 1990-03-29 |
| MX171743B (en) | 1993-11-11 |
| EP0390281B1 (en) | 1992-12-02 |
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